Hinged mold for concrete step structures



A ril 7, 1953 F. KOGL 2,633,620

HINGED MOLD FOR CONCRETE STEP STRUCTURES Filed Jan. 51, 1951 2 Sl-IEETS-SHEET 1 l5 23 I I L-' IL: 5

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April 7, 1953 F. KOGL HINGED MOLD FOR CONCRETE STEP STRUCTURES 2 SHEETS-SHEET 2 Filed Jan. 51, 1951 I II N t\ R 3 N IAYENTOR FRANK K044 ATTORNEY5' mm Vm Patented Apr. 7, 1953 UNITED STATES PATENT OFFICE HINGED MOLD FOR CONCRETE STEP STRUCTURES Application January 31, 1951, Serial No. 208,803

This invention relates to improvements in molds or forms of the monolithic casting of concrete step structures.

I have previously patented a number of molds for this general purpose, illustrative of which is my Patent No. 2,353,676 for Apparatus for Precasting Concrete Stair Structures, and such forms or molds are found in actual, extensive practice to be completely practical in use and operation, and they turn out precast monolithic step or stair structures of durable, attractive and comparatively inexpensive nature. It is, however, necessary each time the mold is filled, and the concrete set, to then strip the mold from the casting and reassemble the mold ready for the next casting operation, and it is this periodic, alternate stripping and reassembly of the mold which consumes a major part of the time in the entire cycle of operation. It is the primary object of my present invention, therefore, to provide an improved mold or form structure wherein the component parts are so hinged together that they may be swung clear or unfolded to, permit the castings to be removed and then closed or restored to working position to reduce to a minimum the work and time necessary for these operations.

It is another object of my invention to provide a hinged type of form or mold which is simple and foolproof, both in its construction and operation, and which lends itself well to use on a production line for turning out steps in large quantitles and at minimum expense. To this end the mold comprises a number of permanently associated component parts which require the manipulation of but a minimum of fastening or connecting means for each operation of removing a casting, and I further support the entire form assembly upon a caster mounted dolly so that it may be wheeled about the shop as necessary for filling or for lifting away the finished casing, as the case may be.

Still another object of my present invention is to provide a form structure which is oscillatably mounted upon a suitable base and in such fashion that the mold may be rocked by hand to bring about a pronounced hammering action of sharp impact characteristics, which type of vibration I find in actual practice to be most efficient in properly settling and compacting the cementitious mixture and elimination of all entrained air or bubbles which would interfere with the production of smoothly surfaced castings.

These and other more detailed and specific objects will be disclosed in the course of the follow- 7 Claims. (Cl. -118) ing specification. reference being had to the accompanying drawings, in which- Fig. 1 is a side elevation of a form according to my invention and showing in dotted lines the positions assumed by certain of the form parts as they are swung open in the process of removing a finished casting. 1 I

Fig. 2 is an enlarged fragmentary vertical sec tion, taken substantially along the line 22 in Fig. l, and particularly showing the manner in which the outer sides of the form are hinged to the structure.

Fig. 3 is an elevation of the form of Fig. 1 viewing the same from the side at which the component treads and risers are molded, and showing one of the form sides as swung partially outward, as both are when removing the casting.

Fig. 4 is a fragmentary horizontal section along the line 4-4 in Fig. l, and particularly showing the manner in which the outer form sides are outwardly flanged in order to form base ledges along the lower edges of the finished casting.

Referring now more particularly and by eference characters to the drawing, I have provided for my present invention a mold shaped and constructed to form a monolithic step structure having three steps with a short platform extension and upright sides, as willbe apparent, but

I do not, of course, limit myself either as to the number of steps which may be cast or as to size, and may, in fact, construct the form or mold sectionally, such as set forth in my Patent No. 2,353,676, so that the form itself may be adjusted to cast step structures having different numbers of steps and of different widths.

Fundamentally the mold comprises inner and outer form sections and, as here illustrated. the inner form section, designated generally at In, is a unitary structure having sides H and connected tread and riser portions '12 and I3 so shaped as to form the inner surfaces of the casting, as will be understood. The outer form section, designated generally at M, is, however, made up of component sides l5 and I6 and what may be termed a front section having tread and riser forming portions I1 and I8 joined together substantially at right-angles to properly shape the exposed surfaces of the steps. The mold also comprises a lower end or base section l9 which is permanently fastened at its opposite ends to a base structure 20 whereon the entire mold rests. As clearly shown in Fig. 1, the step is cast in an upright position at which it rests down upon its lowermost riser, and thus this base section [9 of the outer form is properly shaped upon its upper surface 2! to surface this forward or lowermost riser. As pointed out in my patent previously identified, I cast the steps with. nosings which run around the forward edgesand ends of the treads, and for this purpose the junctions of the tread and riser forming portions lll8 of the outer form are bulged downwardly or channel shaped, as indicated at 22, while the contiguous edges of the outer form sides !--l6 are similarly shaped, as designated at 23. In order to form the nosing along the forward edge of the lowermost tread, the base section [9 of the form is grooved at 24, as indicated in Figs. 1 and As stated, the lower section l9 of the mold is rigidly fastened to the base section and the latter comprises suitably cross braced channels outwardly flanged along their lower edges 26 and adjacent the center, or the center of gravity of the entire mold structure, these channels 25 rest upon a transversely extending trunnion 21, which in turn rests upon a dolly or platform 28 supported by caster wheels 29. This arrangement is obviously such that the entire mold may be oscillated about the axis of the trunnion 21, and for this purpose I affix a hand lever 30 to one side of the base section 29 so that the operator may oscillate the mold in order to pack down the wet cementitious mixture after the mold is filled. Adjacent each end the flanges 26 are provided with downwardly projecting set screws 3! adapted to contact the dolly platform 28 and these screws are so adjusted that the amplitude of the rocking motion of the mold may be regulated and this rocking motion may be prevented while filling the mold by the placement of small wedges, indicated at 32, beneath certain of the screws. Of most importance, however, is the fact that the alternate engagement of the screws 31 with the platform 28 causes the rocking motion to be accompanied by a pronounced hammering effect with successive downward impacts and which type of vibration I find to be most eflicient in settling and compacting the concrete. In fact, actual experience indicates that castings may be turned out which are almost, if not completely, flawless and without the unsightly pockets formed by air bubbles which usually accompany this type of work.

The inner form section [0 is hinged at its lower edge at 33 to the stationary base section I9 of the form, and when in the casting position this inner form section is held in place by a cross channel 34 secured to the adjacent vertical edges of the sides of the form, as set out in detail in my Patent No. 2,353,676. As shown in Fig. 4, this inner form also has outwardly turned flanges I I to close the side and bottom spaces between inner and outer forms. In a mold of the size here illustrated, I contemplate the use of only one of such channels 34, although more may be used and strategically located if desired. In any case, and as also set forth in my patent, I provide the channel 34 with hand screws 35 adapted to bear against the edge of the form sides l5 and I6 so that upon turning these screws I may pull loose the inner form section III in order to swing it out of the way toward the left, as viewed in Fig. 1 and as shown in dotted lines therein. It may here also be noted that the vertical edges of the form sections engaged by the channel 34 are provided with angles 36 in order to provide a fastening for the channel, and furthermore that the sides l5l6 along these edges are turned outward to an L-shaped formation, shown at 31 in Fig. 4, the purpose of which is to cast a ledge or footing 38 along the lower edges of the step sides. Such a ledge and casting means therefor are more fully described in my prior Patent No. 2,289,439 for Method of Precasting Concrete Stair Structures and should require no further description herein.

Along the transverse edge of the base section 19 of the mold, opposite the hinge 33 which carries the inner form section Ill, a similar hinge 39 is provided and attaches the lowermost tread forming portion I! of the outer form so that the same may be swung outward or forward in a direction. opposite the inner form, as also shown in dotted lines in Fig. 1. In the normal casting position of the mold this tread and riser forming portion is held in place by means of threaded eye bolts 40, hinged at 4| to the sides l5|o and engaging in notches 42 formed for their accommodation in the adjacent reinforced edges of the tread and riser portions ll-IB. These bolts 40 carry wing nuts 43 which may be turned up to hold the form tightly closed along the edges of the ends of the treads and rise-rs, but these wing nuts may be slightly loosened and the form swung free very quickly and very easily when it is desired to unfold the mold, as will be understood. In addition, common bolts 44 may be used to bolt the riser portions (8 to adjacent flanged edges of the sides l5l6, and short pilot pins 45 are welded to the sides in order to project through openings 46 in the tread portions (1 to prevent any outward movement of the sides, as well as aid in holding the entire mold in proper alignment. These fastening elements are set forth in greater detail in my Patent No. 2,353,676.

At their lower ends the outer form sides 15-46 depend a short distance below the casting surface of the base section 19, as indicated at 41, and then are hinged at 48 to the side channels 25 so that these outer form sides may swing outward in opposite directions, as indicated in Fig. 3. Additional support is provided for the entire mold structure by inverted V-shaped side frames 49, secured at their upper ends at to the sides i5l5 and hinged at their lower ends at 5| to upper edges of the channels 25 of the base structure, with these hinges 5i coaxial with the hinges 48, as clearly shown. Thus these side frames 49 may swing as a unit with the sides l5-I6, while bracing the mold against any tendency to topple forward or rearward, and in order to clear fastening elements upon the sides of the mold, the frames 49 are offset outwardly at their upper and lower ends, as designated at 52.

In actual use and operation the mold is filled from the top so that the concrete completely fills the cavity between inner and outer forms, and during or following this operation the wedges 32 are removed and the form rocked by manipulation of the hand lever 30 in order to settle the mixture and drive out all air bubbles. The mold is then permitted to set until the casting has cured to the point at which it can be removed, whereupon the hand screws 35 are manipulated to remove the inner form section [0 and it is swung outward or rearward into the clear. The wing nuts 43 are then loosened and the bolts 44 removed, whereupon the outer side and tread and riser forming portions l5-l6-l| and I8 may be swung outward and downward to clear the casting, leaving it standing upon its lowermost riser, resting upon the base section 19 of the mold. In such position the mold sections are all clear and the casting may be lifted and carried away by means of an overhead sling or other suitable mechanism (not shown), and while I have herein shown the mold as exactly vertical in position, I may find it desirable to arrange it at an angle, such as to place the center of gravity of the casting directly over the base section l9 to counteract any tendency of the casting to topple over when the outer mold sections are swung clear. Alternatively, the operator, as the tread and riser portions I'I-IB are swung downwardly, may place a prop beneath one of the risers of the castings until it may be lifted and carried away.

It will be apparent from the foregoing that, as compared to the molds of my prior patents,

this hinged type of mold may be stripped from the casting with a minimum of time and effort, thus to considerably reduce the cost per unit of manufacturing the cast steps. In addition, since all of the form sections remain connected to each other, they cannot become displaced or lost and the folding and unfolding operation is so simple and straightforward that it may be carriedout by even the most unskilled operator without damage either to the mold or to the casting.

' It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described my invention, what I- claim to be new and desire to protect by Letters Patent is:

1. A mold for casting hollow monolithic stair structures with a plurality of treads and risers and integral sides and for casting said structures in an erect position at which the casting rests upon its lowermost riser, comprising in combination," a base structure, complementarily shaped inner and outer forms each having tread and riser forming portions and sides for forming the sides of the casting, hinge means connecting the forms to the base so that the forms when closed will be spaced apart and open at the top to receive the concrete and so that the inner form may be swung out of the casting and the outer form swung away from the casting to leave the casting resting on the base structure when the concrete has hardened, means for holding the forms in such spaced relation, and means for closing the upright opening between the edges of the sides of the inner and outer forms remote from the tread and riser portions while casting.

2. A mold for casting hollow concrete step riser, comprising an elongated base member shaped on its upper side for casting the lowermost riser, an inside form and hinge means connecting this form at its lower edge to the base member, the inside form having connected sides and tread and riser forming portions for casting the inside surfaces of the corresponding components of the step structure, a sectional outside form having a front section with tread and riser forming portions for casting the treads and all but the lowermost riser of the structure, hinge means connecting this front form section at its lower edge to the base member on a hinge axis parallel to that of the inside form, said outside form also including separate sides for casting the outer surfaces of the sides of the step structure, separate hinge means connecting the lower ends of these sides at spaced points to the base section, means for releasably securing the inside and outside forms together in spaced relation while casting, and separate means for releasably securing the front section and sides of the outside form together while casting.

3. A mold for casting hollow concrete step structures with sides and integral risers and treads and for casting said structure in erect positions in which they stand on the lowermost riser, comprising a base structure having an elongated base member shaped on its upper side for casting the lowermost riser, an inside form and hinge means connecting this form at its lower edge to the base member and this form having unitary sides and tread and riser forming portions for casting the inside surfaces of the corresponding components of the step structure, a sectional outside form having a front section with tread and riser forming portions for casting the treads and all but the lowermost riser of the structure, hinge means connecting this front form section at its lower edge to the base meme her, said outside form also including separate sides for casting the outer surfaces of the sides of the step structure, separate hinge means connecting the lower ends of these sides to the base section, means for releasably securing the inside and outside forms together in spaced relation while casting, means for releasably securing the front section and sides of the outside form together while casting, and side frames secured to and depending from the sides of the outer form and hinged to the base structure on axes aligned with the hinge means for these sides.

4. A mold for casting hollow concrete step structures with sides and integral risers and treads and for casting said structures in erect positions in which they stand on the lowermost riser, comprising an elongated base member shaped on its upper side for casting the lowermost riser, an inside form and hinge means connecting this form at its lower edge to the base member and this form having unitary sides and tread and riser forming portions for casting the inside surfaces of the corresponding components of the step structure, a sectional outside form spaced from the inside form to provide an upwardly opening casting cavity, said outside form having a front section with tread and riser forming portions for casting the treads and all but the lowermost riser of the structure, hinge means connecting this front form section at its lower edge to the base member, said outside form also including separate sides for casting the outer surfaces of the sides of the step structure, hinge means connecting the lower ends of these sides to opposite end portions of the base section, means for releasably securing the inside and outside forms together in said spaced relation while casting, means for releasably securing the front section and sides of the outside form together while casting, and means joining upright edges of the sides of the inside and outside forms and closing the space therebetween along these edges.

5. A mold for casting hollow concrete step structures with sides and integral risers and treads and for casting said structures in erect positions in which they stand on the lowermost riser, comprising an elongated base member shaped on its upper side for casting the lowermost riser, an inside form and hinge means connecting this form at its lower edge to the base member and this form having unitary side and tread and riser forming portions for casting the inside surfaces of the corresponding components of the step structure, a sectional outside form having a front section with tread and riser forming portions for casting the treads and all but the lowermost riser of the structure, hinge means connecting this front form section at its lower edge to the base member, said outside form also including separate sides for casting the outer surfaces of the sides of the step structure, separate hinge means connecting the lower ends of these sides to opposite end portions of the base section, means for releasably securing the inside and outside forms together in spaced relation while casting, and means releasably securing the tread and riser forming portions of the front section to the sides of the outside form, and laterally turned flanges on the upright edges of the sides of one of the forms and overlying the corresponding edges of the other form to close the space between the forms.

6. A mold for casting hollow concrete step structures with sides and integral risers and treads and for casting said structures in erect positions in which they stand on the lowermost riser, comprising an elongated base member shaped on its upper side for casting the lowermost riser, an inside form and hinge means connecting this form at its lower edge to the base member, the inside form having connected sides and tread and riser forming portions for casting the inside surfaces of the corresponding components of the step structure, an outside form having a front section with tread and riser forming portions, hinge means connecting this front section at its lower end to the base member, the outside form also including opposed sides, hinge means connecting these sides at lower ends to the base member, means for holding the inside and outside forms in spaced assembled relation while casting, the inside form and front section and sides of the mold being adapted to be swung open with an unfolding action to leave the cast structure standing on its lower riser on the base member when the concrete has sufiiciently hardened, the front section and sides of the outside form having channels for forming nosings around the front and side edges of the treads, the hinge means for the front section being located at the front edge of the nosing of the lowermost tread whereby this form section will swing outward and downward to clear the front edge nosings on the other treads, and the hinge means for the sides being located at a level below the hinge means for the other form parts whereby these sides will also clear the side edge nosings as the sides are swung open.

7. A mold for casting hollow monolithic step units having a plurality of connected treads and risers and integral sides and for casting the step unit in an erect position with the lower riser at the bottom, comprising a base, complementarily shaped inner and outer forms each having tread and riser forming portions and sides for forming the sides of the casting, hinge means connecting the lower parts of the forms to the base so that the forms when closed will be spaced apart and open at the top to receive the concrete and so that the forms may be swung apart on said hinge means to expose the casting, means for holding the forms in such closed position, and means for closing the space between the upright edges of the sides of the forms.

FRANK KOGL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,106,644 Friesecke Aug. 11, 1914 1,545,937 Bonelli July 14, 1925 1,905,897 Cahill Apr. 25, 1933 1,983,757 Hick Dec. 11, 1934 2,440,754 Nagel May 4, 1948 

